Infectious complications of puncture wounds

INTRODUCTION — Puncture wounds are penetrating injuries caused by a pointed object. They are common injuries, particularly to the plantar surface of the foot and other areas of the distal extremities, and occur in all age groups. Infections, ranging from mild soft tissue involvement to osteomyelitis, are the main complication resulting from puncture wound injuries.

The clinical aspects, management, and prevention of puncture wound infections are reviewed here. Infections associated with puncture wounds that occur in specialized settings such as with animal or human bites and water exposure are discussed in further detail elsewhere. (See "Animal bites (dogs, cats, and other mammals): Evaluation and management" and "Human bites: Evaluation and management" and "Soft tissue infections following water exposure".)

Prevention of human immunodeficiency virus (HIV) and infection with hepatitis viruses following a needlestick exposure is also discussed in detail elsewhere. (See "Management of health care personnel exposed to HIV" and "Prevention of hepatitis B virus and hepatitis C virus infection among health care providers".)

EPIDEMIOLOGY

Mechanism of injury — Puncture wounds can occur in a broad array of circumstances. Puncture wounds to the sole of the foot from stepping on an object are the most common. The majority of plantar puncture wounds are due to nails; less commonly, glass, wood, or other metal objects are the source of the puncture. Puncture wounds in the area of the metatarsal-phalangeal joints often penetrate deeper because this is a weight-bearing area [1].

The incidence of infection following a puncture wound is uncertain, as many individuals do not seek medical care following such injuries. As an example, in a survey of 200 general emergency department patients, 44 percent reported at least one prior plantar puncture wound [2]. Of the 156 wounds reported, 50 percent were brought to medical attention, among which the self-reported infection rate was 11 percent.

Soft tissue and systemic infections can also complicate intentional puncture injuries, such as body piercing or injection drug use. These issues are discussed in detail elsewhere. (See "Body piercing in adolescents and young adults", section on 'Health risks and considerations' and "Opioid use disorder: Epidemiology, clinical features, health consequences, screening, and assessment", section on 'Health risks'.)

Risk factors associated with infection — Risk factors associated with infection after a puncture wound include characteristics of the puncture (eg, location and depth of wound), material causing puncture, as well as host comorbidities. Most of the data on risk factors is from studies of plantar puncture wounds or extrapolated from other types of injuries.

In serial analyses of a patient population over a seven-year period, the risk of infection after a puncture wound to the foot had increased in patients who had either injury to the forefoot or wore shoes at the time of injury [3-5]. Superficial wounds generally heal without complications, but deeper penetration from the puncture is a risk factor associated with more serious infections. Retained foreign bodies are also a likely risk factor for infection following puncture wound, based on evidence from lacerating injuries [6].

Diabetes mellitus is a risk factor for serious infection following puncture wound. In a retrospective study of 114 patients hospitalized with puncture wounds, of whom 83 had diabetes mellitus, diabetes mellitus was associated with subsequent osteomyelitis (37.3 versus 6.5 percent) [7]. These patients were also more likely to require multiple operations and 14 times as likely to have a lower extremity amputation.

Other risk factors for infection following a penetrating injury include older age and wound contamination [6,8]. Injury with organic or vegetative material is generally considered to be a risk factor for infection. In addition, immunodeficiency has been associated with puncture-related infections, in particular with organisms acquired from water exposure at the time of injury (see "Soft tissue infections following water exposure"). Some have speculated that immunocompromised hosts are also at risk of infection after tattooing and body piercing [9].

MICROBIOLOGY — Infections complicating puncture wounds can be caused by a variety of microorganisms. Staphylococcus aureus and beta-hemolytic streptococci are common causes of skin and soft tissue infections and can produce wound infections after puncture. Gram-negative bacteria also have been recovered from infected sites. In particular, Pseudomonas aeruginosa is commonly isolated in patients who suffered plantar puncture while wearing tennis shoes, perhaps due to the moist inner sole of the shoe which provides a suitable environment for growth of this organism [10]. In one series, the most common pathogen causing osteomyelitis after a puncture injury was S. aureus in patients with diabetes mellitus and P. aeruginosa in those without [11]. Polymicrobial osteomyelitis occurs more frequently in the setting of diabetes mellitus. (See "Pseudomonas aeruginosa skin and soft tissue infections", section on 'Infection following nail puncture'.)

P. aeruginosa is also the most common organism associated with infections following piercing through ear cartilage. In one systematic review of 39 patients with perichondritis following ear piercing and documented bacterial cultures, 87 percent were caused by P. aeruginosa and 5 percent by S. aureus [12]. Atypical organisms, such as nontuberculous mycobacteria and fungal species, are also reported causes of infections complicating body piercing [13,14]. (See "Pseudomonas aeruginosa infections of the eye, ear, urinary tract, gastrointestinal tract, and central nervous system", section on 'Perichondritis' and "Body piercing in adolescents and young adults", section on 'Localized infection'.)

The range of organisms also depends on the setting in which the injury was sustained. An injury that occurred in the setting of water exposure (eg, punctures from fish hooks, spines of sea creatures, and shells) should raise the possibility of Aeromonas species, Edwardsiella tarda, Erysipelothrix rhusiopathiae, Vibrio species, and Mycobacterium marinum (see "Soft tissue infections following water exposure"). Streptococcus iniae can also cause infections complicating puncture wounds that occur during preparation of fresh seafood for ingestion [15]. In contrast, puncture in a farm setting might prompt consideration of bowel flora of farm animals as possible pathogens.

Fungal and other mycobacterial organisms have been associated with puncture infections from plant or organic material [16,17]. Tooth pick injuries can be associated with polymicrobial oral flora infections [18].

CLINICAL FEATURES — The spectrum of infectious complications following a puncture wound includes cellulitis, soft tissue abscess, septic arthritis, tenosynovitis, necrotizing soft tissue infection, and osteomyelitis. The clinical manifestations of these infections are discussed in detail elsewhere:

●(See "Septic arthritis in adults", section on 'Clinical manifestations' and "Bacterial arthritis: Clinical features and diagnosis in infants and children".)

●(See "Infectious tenosynovitis", section on 'Clinical manifestations'.)

●(See "Necrotizing soft tissue infections", section on 'Clinical manifestations'.)

Infectious complications typically present within several days following a puncture wound. In two studies of adults and children hospitalized for plantar puncture wound infections, the mean time to presentation from the initial injury was four days, although some patients did not present until several weeks later [19,20].

EVALUATION — Evaluation of a patient following a puncture wound includes a careful history to identify risk factors for infection and other complications, examination of the involved area for signs of infection and injury to the tendon, nerve or vascular structures, and assessment for retained foreign material (algorithm 1). Imaging should be performed when there is concern for a deep space infection, necrotizing infection, abscess, or retained foreign body. If infection is diagnosed or suspected, obtaining specimens to identify the microbial etiology is optimal for management, but not always possible.

History and physical examination — A careful history is essential to managing the patient and identifying risk factors for infectious complications of the puncture injury (algorithm 1). The following information are important aspects of the history:

●Description of the penetrating object − Sharp, thin objects can penetrate deeper and are more likely to break off in the soft tissue. A grossly contaminated or organic object (eg, a thorn) can increase the risk of infection with environmental organisms or atypical pathogens [16,21,22]. (See 'Microbiology' above.)

●Scene of the injury − The setting where the injury took place (eg, near or in water or with animal exposure) informs the possibility of exposure to specific environmental organisms that could potentially lead to infection. (See 'Microbiology' above.)

●Depth of penetration − Deeper penetration is a risk factor for more serious injury, abscess, and involvement of deeper structures, such as compartments of the extremities and tendon sheaths.

●Footwear at the time of injury, for plantar injuries − Plantar wounds through the sole of a shoe are associated with P. aeruginosa infections. (See 'Microbiology' above.)

●Determination if a retained foreign body is present − Retained foreign bodies can serve as a nidus for infection and should generally be removed, if possible. (See 'Foreign body assessment and removal' below.)

●Elapsed time since the injury − Patients who present with clinical findings of infection more than seven days after the injury are more likely to have a deep seated infection or atypical pathogen, often with osteomyelitis and/or a retained foreign body [20,23].

●Medical history of the patient (especially history of diabetes mellitus, neuropathy, or vascular disease) − These comorbidities increase the likelihood of deeper penetration and delayed presentation, which in turn increase the risk of infection, complications, and need for surgical intervention [24]. A history of immunosuppression increases the risk of infection with atypical pathogens and may alter the treatment approach.

●Tetanus immunization history − This informs the need and type of tetanus prophylaxis following puncture injury. (See 'Tetanus immunization' below.)

Physical examination should include an extensive evaluation of the involved area and a determination of the site of injury. The area should be inspected and palpated for retained foreign material and signs of infection, including abscess. The vascular, tendon, and neurologic status of the involved area should be evaluated. Even small puncture wounds can result in damage of deeper structures. Pain with passive movement, crepitus, pain out of proportion to exam, and purulence should be clues to deeper infection such as deep space abscess, septic arthritis, osteomyelitis, necrotizing soft tissue infection, or tenosynovitis, even in the absence of superficial changes.

Laboratory tests — Clinical management decisions are generally based on history, physical, and imaging findings. There is limited utility to laboratory tests, such as peripheral white blood cell count and inflammatory markers (eg, erythrocyte sedimentation rate and C-reactive protein). These tests have not been shown to reliably identify or rule out infection following puncture wounds, including deeper infections such as necrotizing soft tissue infection or osteomyelitis, although data are limited [25,26]. In addition, these tests are not predictors of outcome [19]. Thus, clinical management decisions should not hinge on laboratory markers alone, especially in the setting of diabetes mellitus, immunosuppression, or an otherwise concerning clinical exam.

Imaging — Following a puncture wound, imaging can be helpful to evaluate for the presence of a retained foreign body and to evaluate for a soft tissue, joint, or bone infection or delineate its extent (algorithm 1). We perform radiographic evaluation in patients who present with evidence of infection and have not had previous imaging for a foreign body and in patients with relapsing or worsening infection despite local wound care and antibiotic administration. We also perform imaging in patients with suspected deep infection (ie, of the joint or bone), such as those who present with progressive pain several days after the injury, pain out of proportion to superficial exam, pain with passive movement, crepitus, joint swelling, or systemic illness, particularly after deep injuries and with certain host comorbidities (eg, diabetes mellitus, neuropathy, or immunocompromising condition) [27].

Otherwise, the decision to perform imaging to evaluate for a foreign body should be individualized. Some features that support imaging for this purpose include [28]:

●Inability to completely visualize the interior of the wound

●Deep wounds caused by glass

●If the patient believes there is a retained object

●If the object is small, thin, breakable, or brittle

●If the object can easily be buried beneath the skin surface, as with a sewing needle

●If there is severe wound pain, persistent and localized tenderness over the wound, or a painful mass or discoloration under the skin surface

●If there is a missing portion of the penetrating object or if penetrating injury occurred through a rubber shoe [19]

For patients with known or suspected deep infection, magnetic resonance imaging (MRI) is an excellent tool to determine and define the presence of soft tissue abscess, septic arthritis, and osteomyelitis. Computed tomography (CT) should be employed instead of MRI in patients with possible retention of metallic foreign bodies. CT should also be considered in those with concern for soft tissue abscess or soft tissue infection when MRI is not immediately available and time is of importance due to the severity of the clinical presentation. Triple-phase technetium bone scan lacks anatomic detail and specificity, and thus is not as useful for distinguishing bone from soft tissue involvement. Acute bone trauma caused by a foreign object without accompanying infection also can produce a positive bone scan. (See "Nonvertebral osteomyelitis in adults: Clinical manifestations and diagnosis" and "Approach to imaging modalities in the setting of suspected nonvertebral osteomyelitis".)

Otherwise, plain radiographs can be sufficiently sensitive to identify certain foreign bodies, depending on its density, configuration, size, and orientation [28]. Use of an underpenetrated, soft tissue technique may improve the sensitivity of the plain film for foreign bodies [28]. Ultrasonography is also widely available and can be particularly useful to detect radiolucent objects [19,29]. Though specific, it lacks sensitivity for foreign body detection, specifically in the setting of a puncture wounds through a rubber soled shoe. Therefore, in this setting the absence of a visualized foreign body should not be used as a basis for surgical decisions [30]. CT and MRI have also been used to detect foreign bodies; MRI may not be available in a timely fashion and cannot be used to identify metallic foreign bodies. Nevertheless, MRI can be helpful when other techniques have failed to detect the presence of a suspected foreign body.

Identifying the microbial etiology — Debridement of infected tissue and drainage of soft tissue abscesses is an important component of the treatment of puncture wound infections (see 'Debridement and drainage' below). Additionally, it yields specimens for microbiological evaluation to identify the causative pathogen, which may be distinct from pathogens involved in general skin and soft tissue infections. All surgical specimens in the setting of puncture wounds should be sent for aerobic and anaerobic bacterial cultures, with in vitro susceptibility testing of aerobic bacterial pathogens. Additional microbiological tests (eg, mycobacterial and fungal cultures) are warranted if the patient reports an unusual exposure (eg, fish tank, vegetative matter) or if previous routine bacterial cultures have been unrevealing. In general, superficial cultures of wounds should be interpreted with caution, as the results do not correlate reliably with the pathogen in the deeper tissues [31-33]. In patients with simple cellulitis not requiring drainage or debridement, decisions regarding likely pathogens should be made based on the puncture exposure history and patient risk factors, as reliable cultures generally cannot be obtained from such patients.

Blood cultures can be obtained in systemically ill patients, although yield is low and the risk of false positives likely outweighs the benefit in patients without systemic infection. Blood cultures are more likely to be useful in patients who are immunosuppressed or who have necrotizing skin infections.

DIAGNOSIS — The diagnosis of cellulitis or soft tissue abscess following a puncture wound infection is based on clinical findings of skin erythema, edema, and warmth or a tender, erythematous, fluctuant nodule associated with the wound site. A deeper infection (deep-tissue abscess, necrotizing soft tissue infection, septic arthritis, tenosynovitis or osteomyelitis) is suspected in patients with progressive pain several days following the initial puncture injury, pain with passive movement of the extremity, pain out of proportion to external exam (particularly if the injury was deep) and/or persistent signs of soft tissue infection despite initial wound care and antibiotic administration. The level of suspicion should be particularly high for patients who are immunosuppressed, have diabetes mellitus, or have neuropathy, as these patients often present later in their course with increased risk of complicated infection and limited pain on clinical exam [5,27]. These deeper infections can be suggested by imaging results and confirmed by microbial growth on deep wound specimens, joint aspirate, or bone biopsy.

The diagnosis of these infections in general are discussed in further detail elsewhere. (See "Septic arthritis in adults", section on 'Diagnosis' and "Nonvertebral osteomyelitis in adults: Clinical manifestations and diagnosis", section on 'Diagnosis'.)

MANAGEMENT

General management — Patients who develop puncture wound infections should be thoroughly evaluated for the presence of foreign bodies. (See 'Evaluation' above and 'Imaging' above.)

The patient's tetanus immunization should also be noted and prophylaxis given if indicated (table 1). (See 'Tetanus immunization' below.)

Foreign body removal — Easily accessible foreign bodies should be removed as soon as possible. Bedside blind removal in the distal extremities is notoriously difficult and blind attempts should be avoided as they are likely to be unsuccessful and cause further tissue damage. Ultrasound can help localize some foreign bodies and limit the extent of debridement [34,35]. If initial bedside attempts fail in the setting of infection or contaminated/organic matter, the patient should be referred for surgical removal of the foreign body under radiographic visualization. If there is significant concern for vascular or deep structure injury or the potential for injury with removal, patients should also be referred for immediate surgical removal.

Debridement and drainage — Surgical debridement or abscess drainage is an important component of treatment of infected puncture wounds. However, there are limited data informing when surgery should be performed [19]. Surgical debridement is generally warranted for retention of a foreign body in the foot in the setting of infection, rapidly progressive infection, or deep space infection (abscess, necrotic soft tissue, tenosynovitis, septic arthritis, and osteomyelitis). Other clinical features that might portend a worse outcome with infections, such as diabetes mellitus or poor wound characteristics, may be additional reasons to favor surgical intervention. Additionally, we favor surgical intervention when signs and symptoms of infection occur despite prophylactic antibiotics.

Surgical specimens should be submitted for microbiological evaluation to identify the causative pathogen(s). (See 'Identifying the microbial etiology' above.)

Antibiotic therapy — Regimen selection for empiric antibiotic therapy depends on the type of injury and potential other exposures, as below (algorithm 1). In cases of known or suspected osteomyelitis, empiric antibiotic therapy can be held until adequate specimens are obtained for culture as long as the patient is not systemically ill and has no evidence of rapidly progressive or serious soft tissue infection. Subsequently, antibiotic therapy should be tailored to susceptibility testing of wound culture isolates.

Plantar puncture infection — Case series have variably reported either P. aeruginosa or S. aureus as the most frequent causative organism in infections following puncture to the sole of the foot with a nail [19,36]. Thus, it is prudent for empiric antimicrobial treatment of infected plantar puncture wounds to be active against both organisms. Examples include an antipseudomonal beta-lactam-beta-lactamase inhibitor combination (ie, piperacillin-tazobactam) or meropenem with or without methicillin-resistant S. aureus coverage with vancomycin, depending on risk factors (table 2). Patients with potential polymicrobial infection (eg, puncture wound contaminated with dirt or feces) should also receive coverage against anaerobic organisms (which piperacillin-tazobactam and carbapenems would provide). Additional antimicrobial coverage for infected wounds with significant water exposure is discussed elsewhere. (See "Soft tissue infections following water exposure", section on 'Empiric therapy'.)

Once deep wound cultures are available, antimicrobial therapy should be tailored to the susceptibility of wound culture isolates.

If surgical debridement was performed, recovered isolates are susceptible to fluoroquinolones, and there are no contraindications to fluoroquinolones, these agents offer a potential oral option for definitive therapy. Fluoroquinolones can be administered orally after surgery has been performed and the patient is eating; a 24-hour intravenous course is common in such patients. If fluoroquinolone-susceptible P. aeruginosa is isolated, only ciprofloxacin should be used, as the newer fluoroquinolones (levofloxacin and moxifloxacin) have less activity than ciprofloxacin against P. aeruginosa. Levofloxacin and moxifloxacin can be used in mixed infections due to susceptible, aerobic gram-negative bacilli (other than P. aeruginosa) and S. aureus, as these agents have enhanced gram-positive activity.

However, resistance to ciprofloxacin among P. aeruginosa isolates is now frequently seen. If resistance to ciprofloxacin is present, then no oral treatment options for P. aeruginosa are available, and a single active parenteral agent can be chosen based on susceptibility results (table 3). Treatment options for S. aureus resistant to fluoroquinolones include cefazolin for methicillin-susceptible isolates or vancomycin for methicillin resistant isolates. (See "Septic arthritis in adults", section on 'Initial approach' and "Necrotizing soft tissue infections", section on 'Antibiotic therapy'.)

Unless there is evidence of established osteomyelitis upon presentation, antimicrobial therapy for 7 to 14 days is reasonable for plantar wound infections following adequate surgical debridement, particularly in children. Some small studies have reported good outcomes with a relatively short (ie, two weeks or less) course of antibiotics for early bone involvement and septic arthritis following initial management with extensive surgical intervention, including debridement of the infected cartilage or bone and drainage of infected joints [37,38]:

●In one study of 23 adults with infected plantar nail wound infection, the majority due to P. aeruginosa, all patients were cured with ciprofloxacin (400 mg IV twice daily for the first 24 hours followed by 750 mg PO twice daily) following surgery [37]. The duration of therapy was either 7 days for cellulitis or 14 days for early bone involvement (defined as osteochondritis based on radiography or bone scan). Microbiologic analysis revealed P. aeruginosa in 18 cases, S. aureus in 2, and both bacteria in 1; all isolates were susceptible to ciprofloxacin.

●In another study of 77 children with P. aeruginosa osteomyelitis of the foot after puncture injury who underwent surgical debridement, 75 were cured after receipt of antimicrobial therapy for an average duration of 7.5 days postoperatively [38]. Therapy was administered intravenously for the duration of treatment in most patients. Bones involved in this study population included the calcaneus, bones of the midfoot, metatarsals, and phalanges. Only two patients relapsed, with septic arthritis.

Among children, reasons to prolong the duration of therapy beyond 7 to 14 days include delayed surgical debridement or evidence of extensive disease. However, a course longer than four weeks is rarely warranted in children. In adults, if established osteomyelitis is evident on imaging, we feel that a prolonged course of six weeks is appropriate. (See "Nonvertebral osteomyelitis in adults: Treatment", section on 'Introduction'.)

Nonplantar infections — Initial empiric therapy for infections complicating puncture wounds other than plantar nail injuries should mainly include coverage for S. aureus and beta-hemolytic streptococci; cefazolin is a commonly used agent. Epidemiologic factors should dictate the use of other agents to cover additional organisms, including vancomycin for methicillin-resistant S. aureus (MRSA) (table 2). Patients with potential polymicrobial infection (eg, puncture wound contaminated with dirt or feces) should receive broader empiric treatment with activity against gram-negative and anaerobic organisms. Additional antimicrobial coverage for infected wounds with significant water exposure is discussed elsewhere (see "Soft tissue infections following water exposure", section on 'Empiric therapy'). Once deep wound cultures are available, antibiotic therapy should be tailored to the susceptibility of wound culture isolates.

The full duration of antimicrobial treatment and whether intravenous or oral antibiotics can be used depend on the extent of the infection, host characteristics, and the clinical response to infection. These issues are discussed in further detail elsewhere. (See "Septic arthritis in adults", section on 'Treatment' and "Nonvertebral osteomyelitis in adults: Treatment", section on 'Introduction'.)

PREVENTION — Despite the common occurrence of puncture wounds, prospective investigation has not been conducted to identify effective interventions to prevent infection or other complications. For patients who present with puncture wounds without evidence of infection, we assess need for tetanus prophylaxis, local wound care, foreign body removal, and antibiotic prophylaxis, as discussed in further detail below.

Tetanus immunization — Tetanus can complicate a puncture wound, and the patient's tetanus immunization status should be reviewed to ensure protection. Individuals who have completed only the primary series of immunization or who received a booster immunization more than five years previously should receive tetanus toxoid-containing vaccine (0.5 mL intramuscularly) at the time of evaluation. Tetanus toxoid-containing vaccine and tetanus immune globulin (250 units intramuscularly) should be given to patients with puncture wounds who have received fewer than three doses of tetanus toxoid or whose immunization status is uncertain. Approach to tetanus prophylaxis by immunization status is summarized in the table (table 1); refer to the column titled "All other wounds." (See "Tetanus-diphtheria toxoid vaccination in adults".)

Wound care — Cleansing the skin surface surrounding a puncture wound with an iodine-containing or other antiseptic solution, such as chlorhexidine, is routine. There is no clear evidence on the efficacy of irrigation of puncture wounds [1,28]. However, indirect evidence from studies on laceration wound care suggests that puncture wounds should also be irrigated via syringe or other device under moderate pressure [39,40]. The solution to be used is debated, but likely water or saline is sufficient. Most topically-applied antiseptic and antimicrobial products are irritating, partially cytotoxic leading to delayed healing, and can cause contact sensitization. This is discussed further elsewhere. (See "Basic principles of wound management", section on 'Antiseptics and antimicrobial agents'.)

The appropriateness of other treatment options in wound care, including coring and probing the puncture wound are not well established [1,28]. Therefore, we do not routinely recommend them.

Puncture wounds are typically allowed to close by secondary intention (ie, without suturing or stapling). There is a theoretical risk that closure can exacerbate infected wounds by preventing wound drainage. (See "Minor wound evaluation and preparation for closure", section on 'Type of closure'.)

Foreign body assessment and removal — Foreign bodies should be removed when possible to decrease the chance of wound infection and to reduce pain in cases of plantar involvement, which can result in gait disturbances or impairment of mechanical function of the foot. If there is suspicion for a retained foreign body that cannot be visualized, imaging can be helpful to identify one. (See 'Imaging' above.)

Easily accessible foreign bodies should be removed as soon as possible. Inert foreign bodies that are not causing pain or infection that cannot easily be removed may be left in place. Foreign body removal is discussed in further detail elsewhere. (See 'Foreign body removal' above.)

Antibiotic prophylaxis — There are minimal data on the role of antibiotics in preventing infection following puncture wounds. The lack of data makes it difficult to offer recommendations on antibiotic therapy and duration. Thus, the decision to administer antibiotics in high-risk patients is left to the discretion of the treating clinician [41]. We do not routinely offer antibiotic prophylaxis following puncture wounds. However, after a discussion of the risks and benefits, it is reasonable to offer prophylaxis for patients at high risk for subsequent infection, such as those with contaminated puncture wounds (especially with organic matter), diabetes mellitus, immunocompromise, a retained organic foreign body, or injuries through an intact shoe. At a minimum, all patients with puncture wounds should be followed closely for evidence of infection, regardless of whether or not they receive prophylactic antibiotics.

If antibiotic prophylaxis is administered, then the chosen agents should at least provide coverage for S. aureus and beta-hemolytic streptococci (eg, cephalexin). For plantar puncture wounds specifically, prophylaxis should additionally include coverage for P. aeruginosa (eg, with levofloxacin or cephalexin plus ciprofloxacin). Although ciprofloxacin may have greater activity against P. aeruginosa, levofloxacin provides additional gram-positive coverage for prophylaxis. It is reasonable to use fluroquinolones in children for this purpose given the lack of other oral antipseudomonal agents. A duration of antibiotic prophylaxis of three to five days is reasonable.

Follow-up — Close clinical follow-up of patients who are at high risk for infection (eg, those with deep injury to the hand or foot, patients with diabetes mellitus or immune compromise) is warranted for early identification of deep infections that may occur. In particular, patients with diabetes mellitus or neuropathy ideally should be seen by a clinician rather than relying on self-reported symptoms due to their lack of early symptoms and propensity for delayed presentation.

SOCIETY GUIDELINE LINKS — Links to society and government-sponsored guidelines from selected countries and regions around the world are provided separately. (See "Society guideline links: Human bites".)

INFORMATION FOR PATIENTS — UpToDate offers two types of patient education materials, "The Basics" and "Beyond the Basics." The Basics patient education pieces are written in plain language, at the 5^th to 6^th grade reading level, and they answer the four or five key questions a patient might have about a given condition. These articles are best for patients who want a general overview and who prefer short, easy-to-read materials. Beyond the Basics patient education pieces are longer, more sophisticated, and more detailed. These articles are written at the 10^th to 12^th grade reading level and are best for patients who want in-depth information and are comfortable with some medical jargon.

Here are the patient education articles that are relevant to this topic. We encourage you to print or e-mail these topics to your patients. (You can also locate patient education articles on a variety of subjects by searching on "patient info" and the keyword(s) of interest.)

●Basics topics (see "Patient education: Tetanus (The Basics)" and "Patient education: Taking care of cuts, scrapes, and puncture wounds (The Basics)")

SUMMARY AND RECOMMENDATIONS

●Epidemiology

•Mechanisms of injury − Puncture wounds, or penetrating injuries caused by a pointed object, are common injuries. Puncture wounds to the sole of the foot from stepping on an object are the most common. (See 'Mechanism of injury' above.)

•Risk factors − Risk factors for infection include characteristics of the puncture (eg, deeply penetrating wounds, injuries to the forefoot or through shoes), the nature of the puncturing object (eg, contaminated objects, organic or vegetative material), and host comorbidities (eg, increased age, diabetes mellitus). (See 'Risk factors associated with infection' above.)

●Microbiology − Staphylococcus aureus and beta-hemolytic streptococci are common causes of wound infections after puncture. Pseudomonas aeruginosa has been commonly isolated in patients who suffer plantar puncture while wearing tennis shoes. The range of organisms likely involved also depends on the setting in which the injury was sustained (eg, with water or animal exposure) or the material of the injuring object. (See 'Microbiology' above.)

●Clinical features − The spectrum of infectious complications following a puncture wound includes cellulitis, soft tissue abscess, septic arthritis, tenosynovitis, necrotizing soft tissue infection, and osteomyelitis. Infectious complications typically present within several days following a puncture wound. (See 'Clinical features' above.)

●Evaluation and diagnosis

•History and physical examination

-Evaluation of a patient following a puncture wound includes careful history to identify risk factors for infection and other complications (algorithm 1). This includes a description of the penetrating object, scene of the injury, depth of penetration, and the elapsed time since injury. (See 'History and physical examination' above.)

-The involved area should be assessed for signs of infection, injury to the tendon, nerve, or vascular structures, and retained foreign material. (See 'History and physical examination' above.)

•Imaging − We perform radiographic evaluation in patients for whom there is concern for a deep space infection, necrotizing infection, or abscess, or a concern for a retained foreign body (algorithm 1). Plain radiographs or ultrasonography are both widely available and can identify foreign bodies, although the sensitivity of ultrasound is limited and surgical-related decisions should not be based on the absence of findings on ultrasound. For patients with known or suspected deep infection, magnetic resonance imaging or computed tomography is preferred. (See 'Imaging' above.)

•Diagnosis − The diagnosis of cellulitis or soft tissue abscess following a puncture wound infection is based on clinical findings of skin erythema, edema, and warmth or a tender, erythematous, fluctuant nodule associated with the wound site. A deeper infection (deep-tissue abscess, necrotizing soft tissue infection, septic arthritis, tenosynovitis, or osteomyelitis) is suspected in patients with progressive pain several days following the initial puncture injury, pain with passive movement of the extremity, pain out of proportion to external exam (particularly if the injury was deep), and/or persistent signs of soft tissue infection despite initial wound care and antibiotic administration. (See 'Diagnosis' above.)

•Identifying the microbial etiology − If infection is diagnosed or suspected, obtaining specimens to identify the microbial etiology is optimal for management. Superficial cultures of wounds should be interpreted with caution, as the results do not correlate reliably with the pathogen in the deeper tissues. (See 'Identifying the microbial etiology' above.)

●Management

•Foreign body removal − Foreign bodies should be removed in patients who develop puncture wound infections; radiographic guidance can assist in removal. If there is concern for vascular or deep structure injury or the potential for injury with removal, surgical removal is warranted. (See 'Foreign body removal' above.)

•Debridement and drainage − Surgical debridement or abscess drainage is also an important component of treatment of deep infection complicating puncture wounds. (See 'Debridement and drainage' above.)

•Antibiotic therapy − Regimen selection for empiric antibiotic therapy of puncture wound infections depends on the type of injury and potential other exposures (algorithm 1).

-Plantar wounds − Empiric therapy of plantar puncture wound infections should generally include activity against P. aeruginosa and S. aureus. (See 'Plantar puncture infection' above.)

-Nonplantar wounds − Empiric therapy for infections complicating puncture wounds other than plantar injuries should generally include activity against S. aureus and beta-hemolytic streptococci. In either case, a history that suggests possible polymicrobial infection (eg, puncture wound contaminated with dirt or feces) or water exposure should prompt broader empiric therapy. If deep wound cultures are available, antibiotic therapy should be tailored to the susceptibility of wound culture isolates. Duration of therapy depends on the extent of infection. (See 'Nonplantar infections' above.)

●Prevention

•Tetanus administration − The tetanus immunization status should be reviewed for all patients who have sustained a puncture injury. Tetanus toxoid-containing vaccine (0.5 mL intramuscularly) should be administered to those who have completed only the primary series of immunization or who received a booster immunization more than five years previously (table 1). Tetanus toxoid-containing vaccine and tetanus immune globulin (250 units intramuscularly) should be given to patients with puncture wounds who have received less than three doses of tetanus toxoid or whose immunization status is uncertain. (See 'Tetanus immunization' above and "Tetanus-diphtheria toxoid vaccination in adults".)

•Wound care − For uninfected plantar puncture injuries, cleansing the skin surface surrounding a puncture wound with an iodine-containing or other antiseptic solution is routine. (See 'Wound care' above.)

•Antibiotic prophylaxis − There are no trials that have examined the role of antibiotic administration in the prevention of infection following puncture wounds. We suggest not routinely administering prophylactic antibiotics (Grade 2C). It is reasonable to use them in patients at high risk for infection, such as those who have contaminated puncture wounds (especially with organic matter), diabetes mellitus, immunocompromising condition, a retained organic foreign body, or an injury through an intact shoe. (See 'Antibiotic prophylaxis' above.)